General refrigerators include a freezing chamber for maintaining food items at a below zero temperature so as to be kept in a frozen state in storage and a refrigerating chamber keeping food items in unfrozen state in storage. The freezing chamber and the refrigerating chamber are demarcated by an insulating partition to have a determined volume, respectively, and a user cannot change the capacity or volume of the freezing chamber or the refrigerating chamber discretionally.
Thus, techniques allowing users to freely use the internal spaces of refrigerators according to purposes have been developed, and a refrigerator having a convertible chamber is one of those techniques. Namely, besides a general freezing chamber and a general refrigerating chamber, the refrigerator with a convertible chamber includes an additional space partitioned from the freezing chamber and refrigerating chamber and allows for a conversion of the internal temperature of the space as necessary. The convertible chamber can be operated as a freezing chamber or a refrigerating chamber according to a user selection, or may be used as a space maintained to have a different temperature from those of the freezing chamber and the refrigerating chamber.
In order to maintain the internal temperature of convertible chamber in the refrigerator, the internal temperature of the convertible chamber is lowered by using cold air generated by an additional evaporator for the convertible chamber or cold air generated by an evaporator for the freezing chamber or the refrigerating chamber. However, the user may increase the temperature according to circumstances, such as a case in which the user changes a low temperature environment to a high temperature environment. To this end, a heating means is required to increase the internal temperature of the convertible chamber. Here, an electric heater using electrical resistance heat may be used as the heating means.
The electric heater has an advantage in that it can easily control the internal temperature of the refrigerator by regulating the amount of applied current, but has a disadvantage that the necessity of additional power degrades energy efficiency.
Alternatively, a technique for utilizing a high temperature refrigerant, which has passed through a compressor, as a heat source has been proposed. This type of refrigerator heats the interior of the convertible chamber by using heat dissipated to the outside, without the necessity of additional power, improving energy efficiency. However, in order to increase the temperature of the convertible chamber, a refrigerating cycle must be necessarily operated, making it difficult to perform controlling, and since cold air is supplied to the freezing chamber or the refrigerating chamber while the convertible chamber is heated, increasing energy consumption.